Dual check valve assembly for hydraulic control systems



W. H. WORTHINGTON Slept. 30, 1952 DUAL CHECK-VALVE ASSEMBLY FORHYDRAULIC CONTROL SYSTEMS Filed April 19, 195o mm. Tl. f A mlm MPatented Sept. 30, 1952 fp UAn oHEoK VALVE 'ASSEMBLY FOR HYDRAULIQCONTROL SYSTEMS -Wayzu'e'H. Worthington,l Waterloo, Iowa, assigner 'to'Deere Manufacturing Co., Dubuque, Iowa, a corporationof Iowa (originalapplication Marcher, 194s, serial-N0. 18,198, now Patent No. 2,579,134,dated Decem- "ber 18, 1951. Divided and this application April 'Y l-1`9',"1950,'Serial No. 156,810. IniCanadaJanuary 28, 1949 j 5 claims.(c1. 277.-20). f Y` l 9 l 2 l fvThis application isa division ofco-pendngrappassage means at one ,end cooperates with .the

Eplication, Serial No. l8,198,.led March 31, 1948, Anow/Patent "No,vr2,579,134,v dated-1 December 18,

1'95'1. I v i passage means in the outer part inamannel-"different fro-mtheoooperation between Athe vpassage inthe outer part and the passage atthe vother end fT-llis invention ,relates .to a'hydraulic control 5 ofthe inner part. A t the same time, the-rBl/Qril'system and moreparticularly'fto a dua1 check bility of the innerpart does not aiect4the opera- -valve assembly for use :insuch system,4tionallcharacteristics thereofy with respect tothe fThe primarypurposeof the vinvention is vto provalve operating member, 4so thatineither` p osividefimprovementsiin1a'dual check valve of the tion, thecheck valve functions,identicallyex-cept vgeneral classi referred totothe end that desirable. im for Y. different fluid-restricting ycharacteristics refinements; in control are available when selecthrough theselectively differently cooperating tively operating the hydraulic.system at either fluid passagemeans. y s highi'or low speeds. A typicalexample of such Another object of the inventionis` .to ,providehydraulic system is that used as the source of an improved checkvalveassembly 12hat. ,may be 'power' on' an agricultural'tractor foradjusting im- 1 5 easily and economically constructed land one that-plemen'ts drawnby or mounted on the tractor. may be readily providedvfor installation in Ihy- Iny the instances' of a plow, cultivator orplanter, draulic control systems of certain. known types. there fareconditions in which it vis desirable The foregoing and other importantobjects and 4mi'erely vto raise or lower the implement with redesirablefeatures inherent in and .encompassed spfect 'tothe'groundL Undersuchconditions, the -20 bythe-inventionwillbecomeapparentas a comhydra'ulicsystem'may'be operated at full speed. vplete dclosule-of a preferredembodiment-oi, the Under other conditions, however, it maybe desir--invention lis made in the following Idetailed deafbl--to'effect'aratherline adjustment, and itis scription vand accompanying sheetjof ;drawingsVt-lie'refore*necessary that the 'operator have the inwhich f l l"syste'm-well under control'. Of course, the slow- 2D YAYFigure 11 is lafragmentaryvsectional viewof,a speed control for'flne vadjustments couldbe aci -power control casingor housing embodyingfthe c'om'plished bymanually moving' the control valve improved check valve assembly; p toapartially openedl position, but it will beseen f Figure 2 isyatransversesectional viev/,Y-onan thati'such partially Opened'position`is'nota-ccu- .enlarged Seele, "taken ,zSllbStafn'allY '.On.- the linetly :defined Aandl could easily' be disturbed so-,302-2:ofFig11re.1;;and 4 that'thetool' would have to be readjusted. Ac-Figureflislanenlarsed sectional .view rtaken on cording'to' the presentinvention, there is provided the line `3-13 0f Figure-1" I i iadualcheck valve assembly comprising a pair of The ihydrauligpower controlvsystem chosen for entirely'movable-paris, the Smaller of which is thepurposesof illustration is merely typical 0f initially opened tofpermitslow-speed operation 35 many .otherforms'ithatziteould assume.Likeandthe larger 'off which is 'subsequently opened wise, the dualcharacterrvof thecheck tvalve assimultaneously f with iurther opening ofthe .semblyper Selpaltsrm the-selectve-.thlttlirlg smaller part toprovide for full-speed operation, means, maytakeany formother than thatillus- *itbeingjunderstoodf that relativey movement of trated,since thebasic concept of Aa dual. check lthe smaller and larger parts providesfor throttled 40 valve is oldas disclosed in U. aS. l=2a-tent No. lfluidflow.' i 1,215,146. y i v Afurther'irnprovernent provided bythe presentThat portion of the hydraulic systemdllusinvention resides' intheprovision of selectively tratedin Figure 1;represents acontrol or valvecooperative passage means in the smaller vand casing I0 provided nwith amain control ,valve larger part-s so that different ranges of fluid-re-,.45 bore l2 in which -is carried for reciprocationra PstrictingAcharacteristics can'be obtained without main control valve. I4. Arockshaft I6 is vpro- YVaffecting the-operational characteristics ofthevidedwithan arm I8 which iscqnnected at'; 20 assembly. AIn brief,'thecheck valve comprises a to theupper end of thecontrol valve I4.Ahighlargerouter part having an axial boreftherepressure passage 22communicates'withi-the valve through in which is'fs'lidably carriedaninner part 50 bore I2 'interme @:liate itsends andis:normally'outadapted to be initially engaged by a valve-'actuatoil from *upper andlower fluid passages 24 iby Avving member; 'The outer-parthasffluidpassage means of an annular enlarged Vsection .'26eofzthe -meansf andtheinner parthas fluid passage means main valve I4. Exhaust ports 21-areproyded iat yat each of its f 'opposite ends-1 The inner part isopPOSiteendS-'Qf the main-valve'bore I2'. if --reversible 'orinterchangeable Iend fory end and the L55v Since :the Avalve casing andpassages gjtherein `are symmetrical at both sides of the high-pres` surepassage 22, only one portion thereof will be describedfitl beingunderstood that, for all practical purposes, what is said about one-halfof the casing is applicable to the other half.

The passage 24 communicates through a port 28 separated from anadjoining chamber 38 by a valve seat 32 and a dual check valve assemblydesignated generally by the numeral '34.

' A bore 36 coaxial with the port 28 and valve seat 32 serves to carrythe check valve assembly for axial shifting to control the valve seat 32and port 28. A control ball 38 at the inner end of the check valveassembly cooperates with the check l valve assembly and with a ramp 40on the control valve I4 to eiect shifting ofthe check valve assembly tothe right against a spring-loaded second ball 42.

In general, the operation is as follows: It will be assumed that themain control valve I4 is in neutral position as shown.` When 'therockshaft I6 is'moved in a counterclockwise direction to move the valveI4 upwardly, the upper ramp 4I) on the main valve forces the upper ball38 against the left-hand endy of theupper check valve 34 and opens thecheck valve to communicate the upperchamber 3Iland the exhaust port 21via the valve bore I2, the upper passage 24 and the rwardfmoverrient ofthe central enlarged portion 26 ,onthe valve I4, and the lower exhaustport` is" cutfo by a valve port I5. Hence, the lower check valve 34 isopened `by fluid pressure. The lowerchamber 30 is connected by a u'idline 3| to one end of a motor cylinder 33 in which `a piston 35 Viscarried. The other end of the cylinder 33 is connected by a line 31 tothe upper chamber 30.

The details ofthe check valve assembly 34 will be clear from thesectional illustration of the lower check valve in Figure 1 and from theenlarged sectional view inFigures 2 and 3. 'I'he check valve assemblyincludes an outer valve part having inner and outer ends and providedwith an axial bore 46, preferably cylindrical, communicating theopposite ends of the valve part. The inner end of the valve part isinteriorly chamfered at 48 and lies proximate to the innervalveactuating member comprising the ball 38.

` The outer end ofthe valve part 44 is enlarged` to provide a head 50which is exteriorly formed with a poppet or conical seating surface 52land which is interiorlyformed with a conical valve seat 54. The valvesurface 52 cooperates with the valve seat 32 to control the port 28between thev passage 24 and the chamber 30. The interior` seat 54provides a seatfor the spring-loaded ball 42. Since the interior seat 54communicates with the outer end of the bore 46, the ball 42 and the seat54 cooperate to control communication between the outer end of the bore46 and the cham-v ber 30. The action of the spring on the ball 42 servesto normally close the'opening provided by the seats 32 and 54. n

Each valve assembly 34 further includes an inner part 56 in the form ofan elongatedrcom- -outer ball 42 is unseated from the seat 54 by 4 binedmetering and control rod having an intermediate cylindrical portion 58and opposite reduced end portions 6I)y and 62.. Thefcylindrical lportion58 carries the inner part 56 inthe outer part for axial shifting in thebore 46; but the bore 46 and portion 58v are comparably cylindrical tothe extent that the fit therebetween is sufiiciently vclose tosubstantially sealA the bore against the transmission of fluid fbetweenits inner and outer ends. The portions 60 and 62 are of differentlyreduced cross-sectional area as respects the diameter of the bore 46.The reduction in the portion 68 is accomplished by a configurationincluding a pair of opposite parallel flats 6I (Figure 2). A reductionat the portion 62 is accomplished'bythe provision of a single flat 63(Figure 3).

The reduction in cross-section of the portions 68% and 62 as respectsthe cross-sectional area of the bore 46 provides what may be termedfirst and second fluid-passage'means respectively atiopposite ends ofthe inner valve part 56. As will be explained below, these passage meansare selectively cooperative with passage means comprising a plurality of`radially disposed orifices 64, 65 and 66 provided in the outer valvepart 44 adjacent its headedfend. These orices effect uid-transmittingcommunication between the interior of the bore .46 at the head end ofthecheck valve and that portionof the exterior of the outer part 44 thatopens to thepassage 24, it being noted that the port 28 surrounds thatportion of the check valve in which the orifices are formed.

When the combined control and meteringrod 56 is in the position shown inthe lower portion of Figure 1, the inner end portion 68 is proximate tothe valve-actuating ball 38 and the outer end portion 62 is engaged bythe spring-loaded ball 42, the spring serving to hold the entireassembly in closed position. In addition, the portion 62 of the innerpart 56 cooperates rwith certain of the orifices 64, 65 and 66 toprovide restricted fluid communication between the exterior and theinterior of the check Valve, the head end-of the valve still beingclosed by the ball 42. Y

The right-handfend .(Figure 1) of the inner check valve part 56is'provided with .an annular groove 68 that separates the cylindricalportion 58 from the end portion 62. When the inner part 56 is in theposition shown in Figure 3, the annular groove 68 communicates all threeorifices 64, 65 and 66 with the space provided by the ats 63 andassociated portion of the bore 46. In short, the iiud passage betweenthe port 28 and the right-hand end of the check valve is determined bythe cross-sectional area of the space designated by the letter A inFigure 3.

The left-hand end portion 60 projects axially slightly beyond theleft-hand end of the bore 46 and thus engages the valve-actuating ballr38,v

the ball-receiving chamfer at the left end or inner end of the part 44being in axially spaced relation to the ball 38, whereby downwardshifting of the main control valve I4 effects initial shifting of thelower control and metering rod 56 prior to shifting of the outer valvepart 44. When Ythe main control valve member I4 is moved downwardlysufficiently to shift the control 'and metering rod 56 but not the outervalve part v44,*the

means of the outer or right-hand end portion 62 of the rod. Fluidpressure in the lower chamber 30 maintains the seated relation betweenthe outer part 44 andthevalve seat 32 and a limited chamber 30 via thecracked check valve. "The ""#primary functior'iorV Aczrackin''gjthecheckvalve to utjlisextentfis to Aregulatethe `flow-of'-fluidthroughv*fthe check-valvefbyimeans of the in'ne'rrlvalve :part l'-'comprisingthe'-co'ntrol Fand 'metering -rod 56. 'y i-IIence, in those-cases inwhich" it' becomes necesvsary't-open the check valve" assembly 34'against "thepressure of iluid in theffchamber'll, f-the-cpen-'- Ifing]is''ma'de easier by first unseatingf-therv ball '42 and `Ithen 1unseating the outer ipart; This Lvresult `-willffollow-fr'oifn4initialengage'ment by*y theball -38 -unseating the 'outer 'part'.l'This-'result-'will follow from initial engagement bythballjS' with theAcontrol Iand lrrieterng',rd and isubsequent enjg'agemerrt'withY theinner end oi the-fouter'part "44.*, Enga two-waysystem,whichwill beequipped with Ltwo check "valve "assemblies lsimilar 'to Lthe assembly-3 4jthe 'transmission of fluid at high 'pressurebut at' a.' reducedrate will bef-'obtainable cooperating :passage means metering rod iseffected A b'yjvthatamount of.E movementlof .the control ,andmeterng'rod necessary merelyto'unseat the ball without closing the orice 66, atthesame,timemaintaining the closure on the unusedorii'icev B4. At theend of movefment lof the controlr and-metering' rod, the ball 38 picksup the outer partand yboth-'the inner and outer-parts ,movesimultaneouslwthe relative positions between the innerand outerpartsinot' I changing during subsequent'movement.4 It 'is oftendesired'to utiliz-e aparticular. hydrau- ,lic controlsystem' insituationsinlwhich.the fluidvrcharacteristics :of fthe .check :valvefarei,'fdi'fferent lf/romithose.obtainedwhenftheiinner partSBtheposition-sh'ownjin,Figure -1.A

4Eve'nrthoughf the controlfandfrneteringirodA may v-befc'zhanged @end:for end Land the components 1reassembledto--ob'tain'selectivelyfdiierentuidflow characteristics, Etheoperational' characteristicsf'of {theiro'd ais-a control-memberwillnot-be changed, because; 'in-either position Vof-"the rod, whicheverf-end is innermost and adjacent thecontrol lball '138 has the :sameextent o'f vaxial=`projection 'as `the YThe instant disclosureA isbased-fupon-a preferred embodimentfof the'invention. However',it'will-be appreciated that -numerousmodications a'nd alterations maybemade 'fin' the invention Iwithout departingfrom v4the spiritandscopejthereof as Adelined in the 'appended 'claims"JVnat-isclaimed-is: l y "1. Forfusein a valve casing ghavinga vali/1cportfincluding' 1anv outer portion provided 4with 4a "valve seat and aninner portion opening fto'j'a valve-actuating member: .a 'dual valve,comprising,( an'outer part formed externally'to beShiftably carried'invthevalve port and havingoppo- .site .y inner and .outer l,endsandhprovided :With a through: bore communicating .l said tends.; ,meansat the outer fendlof said partincludinglvalve head cooperative to-sea`t. .,on and .be .unseated from the port seatfand means .atvtheinner end .of said part .engageable bythe valve-actuating mem-berto'eiect shifting ,ofk ysaidpart forcausing y,unseating of said valvehead ;4 anjinner-.valvepart having opposite.- ends Vand constructed forreversibility end for end to occupyselectively either. of two adjusted`operating positionsl relative =to:tthe

'outerpart and so :dimensioned intermediategits said endsas rto axiallyslidably `t 1 the vboregin substantially fluid-sealing relationship ineither of said positions; said inner part in either position having oneof its ends projecting axially beyond the inner end of the bore so as tobe initially engageable by the valve-actuating member for axial shiftingprior to engagement by said member of the inner end of the outer partIsaid `inner part in either position having its valve- In the particularembodiment illustrated, the

outer end of the chamber 3D is closed by a threaded plug 'I0 whichserves also as a seat for the end of the spring for the ball 42. Afterthe plug 10 is removed, the spring and ball 42 may be removed, followedby removal of the check valve assembly 34. The control and metering rodmay be changed end for end and the components reassembled, resulting indisposition of the control and metering rod 56 with its end portion 62adjacent the ball 38 and its end portion 60 adjacent the ball 42.

The end portion 6U, including the two flats 6|, is separated from thecylindrical portion 58 of the valve by an annular groove 'l2 (Figure 2).Hence, when the end portion 6l] is arranged for cooperation with theorices 64, and 66, the annular groove 12, in conjunction'with the ats 6I, establishes communication between the interior and exterior of thecheck valveassembly, the iiats pro- Vidingr the two spaces designated atB and C in Figure 2. It will be seen that the combined crosssectionalareaJ of the spaces B and C is greater than the cross-sectional area ofthe space provided at A (Figure 3). Therefore, the fluid-flowactuating-member-proximate end identically arranged relative to saidvalve-actuating member; fluid passage means generally radially of theouter part and spaced inwardly of the valve head to communicate the boreand the exterior of said outer part; rst and second fluid controlportions respectively at and opening generally axially to the oppositeends of the inner part and selectively communicable with'the outer partpassage means according to the selected adjusted including an outerportion provided with a valve' seat and an inner portion opening to avalveactuating member: a dual valve, comprising, an outer part formedexternally to be shiftably carried in the valve port and having oppositeinner and outer ends and provided with a through bore communicating saidends; means at the outer end of said part including la. valve headcooperaable by the valve-actuating member to eect shifting of said partfor causing unseating of said valve head; an inner valve part havingopposite ends and constructed for reversibility end for end 1vtovoccupyselectively either of two adjusted operating positions relative to theouter part and Vso dimensioned intermediate its said ends as to axiallyslidably iit the bore in substantially iluidsealing relationship ineither of said positions; said inner part in either position havingoneof its ends projecting axially beyond the inner end -of the bore soas to be initially engageable by -v the valve-actuating member for axialshifting prior to engagement by said member of the inner end of theouter part, said inner part in either position having y itsvalve-actuating-memberproximate end identically arranged relative to.said valve-actuating member; said outer part havinggenerally radialorice means communi- .cating through the outer part to the bore thereinaxially inwardly of the valve head; means in the inner part providingfirst and second axially separated iirst and secondfluid controlportions re-.

spectively at and opening generally axially to the opposite ends of theinner part and selectively communicable with said orifice means in therespective adjusted positions of said inner part;

and saidrst and second fluid control portions being differently formedand dimensioned to have -different'rluid-ow-restricting effects on theorifice means so as to provide for selectively different uid-owcharacteristics in cooperation with said orifice means according to theselected adjusted position of said inner part.

3. The invention defined in claim 2, further characterized in that: saidiirst and second iluid control portions on the inner part are respeci 8y Q tively in theform'of'inner part end portions oi differently reducedcross-section as respects the bore. .f

4. The invention deiined in claim 3, vfurther characterized inthat: saidfirst uid control portion is in the form of a reduction in cross-sectionof one end of the inner part at one side thereof; said second fluidcontrol portion is in the form of a reduction in cross-section of theother end of the inner part from two sides thereof;V and passage meansgenerally transverse to the shifting axis of the inner part joins saidtwo sides of said second reduction so. that both sides yofisaid v secondreductionare communicable with the oriiice means inthe outer part. K Y,n

5. The invention dened in claim 3, further characterized in that: thebore is cylindrical and the inner part intermediate its ends is acomparable cylinder; the first iiuid-controlportion is in the form of aiiat on a chord of the inner part cylinder at one end so as to effect areduction in the cross-section of one end of the inner part; the secondHuid-control portion is in the form of a pair of flats on twocircumferentially spaced chords of the inner part cylinder so .as toeffect a greater reduction in the cross-section of the other end of theinner part; and circumfer- V ential passage means joins thelats of saidpair.

WAYNE H. WOR'II-IINGTON.

REFERENCES CITED The following references are of record inthe file ofthis patent: l

UNITED sTii'rEs PATENTS Date.

